Law school, especially the first year, is extremely rigorous and can trigger drinking in people with and without drinking problems. Difference is that people without problems can leave it behind when they need to study, have a final coming up, etc. People with a drinking problem cannot. And if you continue drinking, your performance will suffer. I know, I was there.
You should also know up-front that both law students and lawyers have high incidents of substance abuse, with alcohol being a popular drug of choice. You will encounter it at social events, firm recruiting events, etc. Please get help to navigate these mine fields. You should definetley check with the school, because most law schools recognize this tendency and offer programs/counseling for alcohol and drug abuse.
Good luck!